Chronic low back pain (cLBP) is one of the most common conditions treated in the primary care setting, yet treatment remains unsatisfactory for many patients. The opioid crisis has underscored the urgency of alleviating patients' cLBP with effective therapies, including evidence-based nonpharmacologic approaches. Mindfulness is effective for the treatment of cLBP yet remains underutilized as it has not been regularly woven into the outpatient clinical setting. Mindfulness-based Stress Reduction (MBSR) is now recommended by the American College of Physicians for initial treatment of cLBP. The next necessary step is to do a pragmatic clinical trial (PCT) with the goal of informing decision makers how this program can work in a real-life clinical setting and its impact on outcomes. We propose a PCT of this program titled ?OPTIMUM? (Optimizing Pain Treatment In Medical settings Using Mindfulness). It will be conducted with three health care system (HCS) sites (Boston Medical Center, MA, UPMC, Pittsburgh, PA, and Piedmont Health Services, in partnership with the University of North Carolina, Chapel Hill). Our primary goal is to determine the impact of this intervention under usual care circumstances. The rationale for this project is to inform key decision-makers how nonpharmacologic treatment can be integrated into routine care and the impact of this program on key outcomes. The specific aims UG3 Phase are the following: Aim 1: To plan and test a mindfulness clinical pain program, OPTIMUM, in the 3-HCS sites prior to the full PCT during the first 12- months of the project. Clearly defined milestones will be reached with guidance from the Collaboratory Coordinating Center. The specific aims UH3 Phase are: Aim 2. To integrate and test an evidence-based mindfulness clinical pain program, OPTIMUM, for patients with cLBP in the primary care setting. Four- hundred-fifty persons with cLBP ? 18 years of age will be randomized to 1) OPTIMUM (n=225) + PCP Usual Care; or 2) PCP Usual Care (n=225). Primary Hypothesis: patients in OPTIMUM will have significantly reduced pain at completion of the program and 6- and 12-months later, as compared to PCP Usual Care. Hypothesis 2: patients in OPTIMUM will have significantly improved physical and psychological function at completion of the program and 6- and 12-months later, as compared to PCP Usual Care. Hypothesis 3: patients in OPTIMUM will be less likely to start and more likely to reduce or stop an opioid prescription for cLBP as compared to those in PCP Usual Care. Aim 3. To evaluate use of healthcare resources by patients as documented in the electronic health record. Hypothesis: patients in OPTIMUM will have fewer emergency department visits, fewer hospitalizations, fewer imaging (CT/MRI), and fewer procedures (injections, surgery) than PCP usual care. Aim 4. To evaluate PCP and practice site use of, satisfaction with, and integration of OPTIMUM. Delivering a group mindfulness pain program in primary care is innovative and we expect it will increase the quality of, and satisfaction with cLBP care.